Oversubscription on multicore processors

Abstract: Existing multicore systems already provide deep levels of thread parallelism. Hybrid programming models and composability of parallel libraries are very active areas of research within the scientific programming community. As more applications and libraries become parallel, scenarios where multiple threads compete for a core are unavoidable. In this paper we evaluate the impact of task oversubscription on the performance of MPI, OpenMP and UPC implementations of the NAS Parallel Benchmarks on UMA and NUMA multisocket architectures. We evaluate explicit thread affinity management against the default Linux load balancing and discuss sharing and partitioning system management techniques. Our results indicate that oversubscription provides beneficial effects for applications running in competitive environments. Sharing all the available cores between applications provides better throughput than explicit partitioning. Modest levels of oversubscription improve system throughput by ...

• Type: Journal
• Year: 2010
• Where: IPPS
• Authors: Costin Iancu, Steven Hofmeyr, Filip Blagojevic, Yili Zheng
• Keywords: Distributed And Parallel Computing, Explicit Thread Affinity, IPPS 2010, Nas Parallel Benchmarks, NUMA Multisocket Architectures